Success of Custom Hearing Protection Devices within an Enhanced Hearing-Conservation Program aboard a US Navy Warship
Technical Report,01 Oct 2013,30 Sep 2015
NAVAL SUBMARINE MEDICAL RESEARCH LAB GROTON CT GROTON United States
Pagination or Media Count:
This report presents hearing sensitivity data from naval personnel working aboard a littoral combat ship, the USS FREEDOM LCS-1, in a noisy ship environment who participated in an enhanced hearing-conservation program that issued custom-molded earplugs. Over a period of 5 years, 11 cases of significant threshold shifts STSs were recorded in the approximately 80 sailors who had been enrolled in the enhanced hearing conservation program. However, the entire crew had rotated off the ship by Year 4, resulting in less onboard noise exposure. The best estimated incidence of STS is 5 per person-year 95 confidence limits 2 to 9. However, temporary and false negative shifts indicate that the incidence of permanent threshold shifts is likely below 3 per person-year. Average shifts from single and multiple frequencies were calculated, with no consistent trends found over time. For comparison, a similar analysis of the crew of a destroyer, the USS STERETT DDG-104, produced a significantly higher estimated STS incidence of 13 per person-year 95 confidence limits 9 to 19.
- Submarine Engineering
- Anatomy and Physiology